Psychosis could be linked to immune disorders

A recent study calls for routine blood screening of patients with first-episode psychosis because of a possible link with the presence of NMDAR antibodies.

Traditionally there has been minimal overlap between the work of psychiatrists and immunologists. However, research published recently in The Lancet could eventually lead to greater collaboration between the two specialisms.

Funded by the Medical Research Council and carried out by researchers from Oxford University, Cambridge University and King's College, London, the case control study compared levels of antibodies with brain receptors found in the blood of people without mental illness and people with a first episode of psychosis. The conclusion was that, in some patients, there may be a link between the presence of NMDAR antibodies and their mental illness. However, there were no clinical characteristics that separated those with NMDAR antibodies from those without. Therefore, the researchers suggested that the only way to detect patients with potentially pathogenic antibodies was universal screening of those with first-episode psychosis at first presentation.

While psychiatrists and other mental health professionals across the UK will no doubt be interested in the findings, the NHS Choices website sounds a note of caution. It points out that only 3% of people with psychosis in the study had the NMDAR antibody and that none of those was in the small control group of 105 people. "We'd need to test many more people to be sure that nobody without a mental health condition had antibodies against NMDAR," says the site.

While this research specifically relating to NMDAR antibodies breaks new ground, the possible link between the immune system and psychosis has been hypothesised for many years. In 1895, the eminent Canadian physician William Osler described the occurrence of psychosis in patients suffering from systemic lupus erythematosus (SLE). The link between autoimmune diseases and mental illness has been actively investigated since the 1930s, when autoantibodies were first reported in a schizophrenia patient.

Despite the cautious response from the NHS and others, the authors of the new study are convinced that it's an important step forward in mental health research. "The implications of this are that there are patients in mental health services now who will have these antibodies and could potentially be treated in a very different way," explained Dr Belinda Lennox, a clinical psychiatrist at the University of Oxford. "I think this is a really exciting advance for psychiatry as a whole, and every psychiatrist and patient with psychosis needs to be aware of this and to look for it and treat it assertively when we find it."